1. Field of the Invention
The present disclosure relates to an input device, and more specifically to a touch panel and manufacturing method thereof.
2. Description of the Related Art
Present touch panels of input devices are of different types: Resistive type, Capacitive type and Optical type, wherein capacitive touch panels have a stack-up structure that is stacked by a sensing electrode layer, an insulation layer and a conductive wire layer on a substrate, wherein the touch panel combines with a control circuit and a liquid crystal display module to be disposed in electronic devices that include a touch option.
In a conventional process, while a finger or a touch stylus touches or approaches a capacitive touch panel, electric potential signal changes at the touch position, based on which a control circuit determines coordinates of a touch position. Thus, the touch panel is normally provided with a touch region for users to touch. Meanwhile, there is a peripheral region encompassed with the touch region that is used for disposing the conductive wire layer to connect with an external control circuit.
Conventional touch panels are illustrated in the following drawings. FIG. 1 is a flow chart of a typical manufacturing method for a traditional touch panel. FIG. 2 is a section view of a traditional touch panel, and FIG. 3 is a planar bottom view of a traditional touch panel.
A manufacturing method for a traditional capacitive touch panel disclosed here, comprises the following seven steps:
At Step S1: disposing a first wire layer 200 on a transparent substrate 100, to form a plurality of bridge wires 210 in a touch region 110;
At Step S2: disposing an insulation layer 300 in the touch region 110 of the transparent substrate 100, to form a plurality of insulating bridges 310, which are equivalently overlaid on middle section of the bridge wires 210, and both ends of the bridge wire 210 are exposed outside to the insulation bridges 310;
At Step S3: disposing a sensing electrode layer 400 in the touch region 110 of the transparent substrate 100. Further, a plurality of X-axis electrodes 410 electrically isolated from each other and a plurality of Y-axis electrodes 420 electrically connecting with each other are formed in the touch region 110. The Y-axis electrodes 420 are electrically connected to each other by a connecting line 430. The connecting line 430 equivalently crosses the insulating bridge 310 and spaces the X-axis electrodes 410. The two X-axis electrodes 410 located at either side of the connecting line 430 are separately connected to one end of the bridge wire 210.
At Step S4: baking the sensing electrode layer 400 to cure the X-axis electrodes 410, the Y-axis electrodes 420, and the connecting line 430;
At Step S5: disposing a second wire layer 220 in the peripheral region 120 of the transparent substrate 100 to form a plurality of peripheral wires 230, wherein the peripheral wires 230 are electrically connected to the X-axis electrodes 410 or Y-axis electrodes 420;
At Step S6: disposing a protective layer 500 to cover the whole substrate 100 and the stack-up disposed on the substrate 100; and
At Step S7: baking the protective layer 500.
According to steps S1 to S7, the protective layer 500 prevents electrodes 410, electrodes 420, and the connecting line 430 from being oxidized because of the long exposure to air, or being corroded by corrosive liquid or gas. Although the protective layer 500 can protect the sensing electrode layer 400 that has already been made, it is unable to protect the sensing electrode layer 400 from being exposed to the air during the manufacturing process. Thus, the electrodes 410, 420 and the connecting line 430 are easily oxidized by the oxide in the environment during the baking process as step S4 is executed without protective layer 500, which leads to a variation of resistance value that affects recognition capability of a system for coordinate positions of the axis.
Moreover, the second wire layer 220 is disposed after the sensing electrode layer 400 of step S4, that is the sensing electrode layer 400 is exposed to the air while the second wire layer 220 is disposed. Thus, the sensing electrode layer 400 is easily oxidized by the steam in the air, or corroded by corrosive liquid and gas. As a result, resistance value of the electrodes 410, 420 and the connecting line 430 becomes unstable.